TWI396703B - Film forming composition and organic electroluminescent element - Google Patents

Abstract

A film-forming composition that attains an improvement in the solubility of a hole-injecting/transporting material and/or an electron-accepting compound and has a drying rate appropriate for stable formation of a uniform coating film, being suitable for the formation of a hole-injecting/transporting layer. This composition comprises a hole-injecting/transporting material and/or an electron-accepting compound and a liquid in which the hole-injecting/transporting material and/or the electron-accepting compound are dissolved. This liquid mainly contains a solvent whose molecule has an aromatic ring and/or an aliphatic ring and an oxygen atom and which has either a boiling point of at least 200°C or a vapor pressure of 1 torr or lower at 25°C.

Description

Film forming composition and organic electroluminescent element

The present invention relates to a film-forming composition used for forming a hole injection/transport layer of an organic electroluminescence device, and an organic electroluminescence device in which a hole injection/transport layer is formed from the film-forming composition.

The hole injection layer for forming an organic electroluminescent device by a wet film formation method is described in Patent Documents 1 to 3 below.

Document 1 discloses the use of an aromatic diamine-containing polyether containing a hole transporting material and tris(4-bromophenyl)ammonium hexachloroguanidinium salt (TBPAH) as an electron accepting compound dissolved in dichloromethane. The solution and the method of forming a hole injection/transport layer by spin coating.

Document 2 discloses a method of forming a hole injection layer by a spin coating method using a 1,2-dichloroethane solution containing a polyether having an aromatic diamine.

Document 3 is a 1,2-dichloro group using a mixture of 4,4'-bis[(N-(m-tolyl)-N-phenylamino)biphenyl and an electron accepting compound of antimony pentachloride. An ethane solution and a method of forming a hole transport layer by spin coating.

The composition in which the hole injection/transport layer is formed by the inkjet method is as described in Patent Documents 4 and 5 below.

Document 4 discloses coating of copper phthalocyanine or a conductive polymer of polyethylene dioxythiophene (PEDT) and polystyrene sulfonic acid (PSS) in a mixed solvent composed of water and a lower alcohol. liquid.

Document 5 discloses a coating liquid in which PEDT and PSS are dispersed in a solvent composed of water, ethanol, and dipropylene glycol.

Patent Document 1: Japanese Laid-Open Patent Publication No. Hei. No. Hei. No. Hei. No. Hei. No. 2000-36. The composition for coating a hole injection/transport layer used in the conventional wet film formation method is a water-containing solvent as a solvent, as disclosed in Japanese Laid-Open Patent Publication No. 2004-204114. Organic electroluminescent elements generally suffer from damage due to moisture. Therefore, when the aqueous composition is used as such, it is necessary to remove the water as much as possible after film formation. It is quite difficult to completely remove the water in the hole injection/transport layer after film formation. Since moisture remains in the film, the characteristics of the conventional organic electric field light-emitting element are lowered. Since the difference in residual water content in the film forming step is uneven, the characteristics of the respective elements are not constant when the organic electroluminescent element is manufactured.

4,4'-bis[(N-(m-tolyl)-N-phenylamino)biphenyl, aromatic diamine containing material as a hole injection layer and a hole transport layer forming material of an organic electric field light-emitting element The polyether or the like generally has a low solubility in a solvent. Therefore, when a thin layer of an organic material is formed by a wet film formation method, it is difficult to prepare a solution having an appropriate concentration.

Affinity with the underlayer will be important in forming a highly uniform hole injection/transport layer. Therefore, the solvent of the solution used in the wet film formation method is required to have a property of dissolving the hole injection/transport material and having high affinity with the underlayer. However, it is quite difficult to prepare a solution that satisfies the balance of these two requirements.

When a plurality of laminated organic light-emitting elements are formed by an inkjet film formation method, the drying speed of the coating liquid is one of the most important factors in the efficiency of the left and right manufacturing steps. For example, when a high vapor pressure solvent is used, when the coating liquid is ejected from the ejection nozzle toward the coating surface, the solvent is vaporized, so that the nozzle is easily clogged, and it is difficult to form an organic layer having high uniformity.

An object of the present invention is to provide a composition for film formation which is not water-containing when a hole injection layer or a hole transport layer of an organic electroluminescence element is formed. Another object of the present invention is to provide a solubility to a hole injection/transport material, a discharge stability from a spray nozzle, an affinity between a film formed film and a primer layer, and a suitable coating layer can be formed. At least one (preferably all) of the film forming composition having improved drying characteristics and the like.

Furthermore, another object of the present invention is to provide an organic electroluminescence device which forms a hole injection/transport layer using the film formation composition.

The film-forming composition of the present invention is a composition used for film formation of a hole injection/transport layer of an organic electroluminescence device, and contains a hole injection/transport material and/or an electron acceptor compound, and dissolves the material. And a liquid film-forming composition of the compound, characterized in that the liquid system has an aromatic ring and/or an alicyclic ring and an oxygen atom in the molecule, and contains a vapor having a boiling point of 200 ° C or higher or 25 ° C. The solvent is pressed at a pressure of 1 torr or less (hereinafter referred to as "first solvent"), and the first solvent content in the composition is 3% by weight or more.

The organic electroluminescence device of the present invention is a hole injection/transport layer formed of the film formation composition.

According to the present invention, the solubility of the hole injection/transporting material and/or the electron accepting compound is improved, and the appropriate drying speed capable of stably forming a uniform coating film is suitable for forming the hole injection/transport layer. Membrane composition.

A solvent composed of a compound having an aromatic ring and/or an alicyclic ring and an oxygen atom in the molecule, and solubility in an electron accepting compound such as a hole injection/transport material such as an aromatic amine compound or an aromatic boron compound. Higher, it will increase the concentration of the hole injection/transport material and/or electron acceptor compound in the composition. Therefore, the solvent will modulate the composition with the optimum concentration or viscosity. The first solvent has a boiling point of 200 ° C or higher, or a vapor pressure at 25 ° C of 1 torr (133 Pa) or less, and is extremely unlikely to evaporate. Therefore, when the first solvent is used and the coating is carried out by the inkjet method or the spray method, it is possible to prevent the nozzle from being clogged by the ejection nozzle due to evaporation of the solvent. By suppressing the occurrence of the first solvent evaporation from the coating film, the coating film is self-leveling, whereby a film having a uniform thickness without spots can be formed.

In this case, since the film-forming composition of the present invention is less likely to be dry and has a good leveling property, it is suitable for forming a film for injection/transport layer by an inkjet method and a spray method.

When the liquid in the film-forming composition of the present invention is not hydrated, the characteristics of the obtained element will be more stable and the hole transporting ability will be improved.

The present inventors have found that a uniform film can be formed by an inkjet method, and it is preferable to use a solvent having a relatively low boiling point or a high vapor pressure and a solvent having a high boiling point or a low vapor pressure in an appropriate mixing ratio.

In one aspect of the invention, the liquid system contains the first solvent and the second solvent (the molecule has an aromatic ring and/or an alicyclic ring, and an oxygen atom, and does not belong to the first solvent), and the weight of the first solvent When the content ratio is W ₁ and the weight content of the second solvent is W ₂ , the weight ratio W ₂ /W ₁ of the second solvent to the first solvent is 1 to 20. In order to flatten the film, W ₂ /W _{1 is} particularly preferably 1 to 2.5.

In another aspect, the liquid system contains a first solvent (which is an aromatic ester and has a weight content W _a ), and a low evaporating solvent (which has a higher boiling point than the aromatic ester or a vapor pressure at 25 ° C) It is low and belongs to the first solvent, and has a weight content W _b ), and the weight ratio W _a /W _b is 1 to 20. In order to improve the flatness of the film, W _a /W _{b is} preferably 1 to 2.5. In this case, it is preferred to use a benzoate for the aromatic ester, and an acetate having an aromatic ring for the low evaporative solvent.

In the present invention, the liquid can be used substantially only of the first solvent, whereby the solvent evaporation state from the composition can be suppressed at the time of film formation.

In the film-forming composition of the present invention, the hole injection/transport material may be an aromatic amine compound, and the electron acceptor compound may be an aromatic boron compound and/or a salt thereof.

Since the organic electroluminescent element is formed by laminating a plurality of layers composed of an organic compound, it is preferable that each layer belong to a uniform layer. When the layer formation is carried out by the wet film formation method, it is preferable to reduce the present invention as much as possible because moisture is mixed into the composition for layer formation, and moisture is mixed into the coating film to impair the uniformity of the film. The moisture content in the film-forming composition.

In the organic electroluminescent device, a material which is significantly deteriorated by moisture (for example, aluminum constituting a cathode) is used. Therefore, the film-forming composition of the present invention preferably has a water content of 1% by weight or less, thereby improving film uniformity. The deterioration of the organic electric field light-emitting element is prevented, in particular, the cathode is prevented from being deteriorated.

The film-forming composition of the present invention is suitably used as a coating liquid for forming at least one of a hole injection layer and a hole transport layer.

The film formed using the film-forming composition of the present invention will have superior uniformity. The film system may be a hole injection/transport layer of the patterned electrode, or a hole injection/transport layer formed between the pixels by the partition walls and formed in a specific region of the remaining substrate surface.

Hereinafter, preferred embodiments of the present invention will be described in more detail.

The film forming composition of the present invention is preferably a coating liquid which is formed between the anode and the light-emitting layer and is provided with a hole injection layer and/or a hole transport layer.

In the present specification, when the layer between the anode and the light-emitting layer is one layer, it is referred to as a "hole injection layer", and when two or more layers are used, the layer adjacent to the anode is referred to as "electricity". The hole is injected into the layer, and the remaining layers are collectively referred to as the "hole transport layer." Further, a layer provided between the anode and the light-emitting layer is collectively referred to as a "hole injection/transport layer".

[Liquid in film forming composition]

The film formation composition of the present invention includes a hole injection/transport material and/or an electron acceptor compound (which forms at least one of a hole injection layer and a hole transport layer of the organic electroluminescence element), And a liquid in which the holes are injected/transported and/or the electron accepting compound is dissolved.

The liquid system contains a first solvent having an aromatic ring and/or an alicyclic ring and an oxygen atom in the molecule and having a vapor pressure of 200 ° C or more or 25 ° C and a vapor pressure of 1 torr or less. The aromatic ring system may be any of an aromatic hydrocarbon ring and an aromatic heterocyclic ring, and is preferably an aromatic hydrocarbon ring.

The concentration of the first solvent in the film-forming composition is usually 3% by weight or more, preferably 10% by weight or more, more preferably 50% by weight or more, and still more preferably 80% by weight or more. It is preferable that the first solvent is 50% by weight or more of the liquid contained in the composition. It is also possible that the liquid in the composition is substantially composed only of the first solvent.

The first solvent is not particularly limited as long as the boiling point is 200 ° C or higher, or the vapor pressure at 25 ° C is 1 or less or less, and the upper limit of the boiling point or the lower limit of the vapor pressure is not particularly limited. The preferred range of the boiling point and the vapor pressure varies depending on factors such as the ratio of the first solvent in the total solvent and the type of other solvent to be used, and it is not essential to generalize, but usually the boiling point of the first solvent is preferably about 200 to 300 ° C, and 25 The vapor pressure at ° C is preferably about 0.001 to 1 torr.

The first solvent may, for example, be methyl benzoate, ethyl benzoate, isopropyl benzoate, propyl benzoate, n-butyl benzoate, dimethyl phthalate or 2-phenoxyethyl acetate. An aromatic ester such as phenyl propionate.

The liquid system may contain a plurality of first solvents. In this case, the liquid may contain a first solvent having low evaporability and a first solvent having high evaporability.

The liquid may contain at least one type of first solvent and at least one type of second solvent (having an aromatic ring and/or an alicyclic ring in the molecule, and an oxygen atom, and not belonging to the first solvent).

The second solvent system may, for example, be an aromatic ester other than the first solvent such as phenyl acetate or ethyl pentafluorobenzoate; an aromatic ether such as anisole or phenethyl ether; cyclohexanone, methylcyclohexanone or a ring; An alicyclic ketone such as pentanone, cycloheptanone or cyclooctanone; an alicyclic alcohol such as cyclohexanol, methylcyclohexanol, cyclopentanol, cycloheptanol or cyclooctanol.

The second solvent has a boiling point of less than 200 ° C and a vapor pressure at 25 ° C of more than 1 torr. The second solvent preferably has a boiling point of 150 ° C or higher or 25 ° C and a vapor pressure of 5 torr or less. The second solvent preferably dissolves the hole injection/transport material and the electron acceptor compound sufficiently, and may have a solubility greater than that of the first solvent.

The liquid system may further contain at least one type of first solvent and at least one type of second solvent as described above.

In this case, the second solvent by weight of the liquid content of ₂ W, and the content of the first solvent weight ratio of W ₁ to W ₂ / W ₁ is preferably 1 to 20, particularly preferably 1 to 19. When the first solvent is less than this range, the effect of the present invention produced by using the first solvent cannot be sufficiently obtained, and conversely, the second solvent other than the first solvent cannot be sufficiently obtained, and an effect of adjusting the drying rate is attempted. The ratio W ₂ /W ₁ can also be set to 3 to 19.

In order to improve the flatness of the film, W ₂ /W _{1 is} preferably from 1 to 2.5.

In the present invention, as described above, the liquid may contain a plurality of first solvents. For example, it may contain a first solvent having a high evaporability and a first solvent having a low evaporability. Specifically, a vaporizable first solvent having a vapor pressure of 200 to 240 ° C or 25 ° C and a vapor pressure of 1 to 0.1 torr, and a vaporization pressure of 250 ° C or higher or a vapor pressure of 25 ° C or less may be a low evaporation property of 0.1 torr or less. The first solvent is used in combination. In this case, the high resistance of the first solvent was evaporated by weight of the composition of the content of W _a, the low volatility of the first solvent weight ratio of the content of W _b W _a / W _b is preferably 1 to 20, especially 1 to 19 It is better.

In order to improve the flatness of the film, W _a /W _{b is} particularly preferably 1 to 2.5.

As the higher solvent, the first solvent is preferably a benzoate such as ethyl benzoate. As the first solvent having a lower evaporating property, an aromatic ring-containing acetate such as 2-phenoxyethyl acetate is preferably used. A film formed by coating a liquid containing ethyl benzoate and 2-phenoxyethyl acetate will have superior flatness.

The first solvent having higher evaporation property and the first solvent having lower evaporation property preferably have a difference in boiling point of 20 ° C or higher, particularly preferably 40 to 100 ° C, or preferably a vapor pressure difference of 0.09 torr or more at 25 ° C. Especially with 0.2~0.999torr.

The solubility of the highly vaporizable first solvent to the hole injection/transport material and the electron acceptor compound may be higher than that of the low evaporation first solvent.

The liquid may contain three or more kinds of first solvents. For example, the liquid may contain three or more kinds of first solvents having different evaporative properties. In this case, when the first solvent weight content having the highest evaporability is W _H and the first solvent weight content having the lowest evaporability is W _L , W _H /W _{L is} preferably 1 to 20. Especially 1~19 is better, and 1~2.5 is better.

The liquid may further contain other solvents, such as at least one aromatic hydrocarbon such as benzene, toluene or xylene; or at least 1 such as N,N-dimethylformamide or N,N-dimethylacetamide. One kind or two or more kinds of guanamines; dimethyl hydrazine.

However, as described above, the liquid is preferably contained in the first solvent in an amount of 50% by weight or more, and may be substantially composed only of the first solvent.

[hole injection/transport material]

The hole injection/transport material may, for example, be an aromatic amine compound, a phthalocyanine derivative, a porphyrin derivative, a metal complex of an 8-arylquinoline derivative having a diarylamine group, or an oligothiophene derivative. Things and so on. Further, a polymer compound having a hole transporting portion in the molecule can also be used. These hole injection/transport materials may be used singly or in combination of two or more.

The polymer compound having a hole transporting portion in the molecule may, for example, be a polymer aromatic amine compound containing a main skeleton having an aromatic tertiary amine group as a constituent unit. Specific examples are hole injection/transport materials having a repeating unit structure as shown in the following general formula (I).

In the formula (I), Ar ^{1 1} to Ar ^{1 4} are each a divalent aromatic ring group which may independently have a substituent; and R ^{1 1} to R ^{1 2} are each a monovalent aromatic ring which may have a substituent and may have a substituent. The group X is directly bonded or selected from the following linking groups.

The "aromatic ring group" encompasses both "a group derived from an aromatic hydrocarbon ring" and "a group derived from an aromatic heterocyclic ring".

In the above general formula (I), Ar ^{1 1} to Ar ^{1 4 are} preferably a divalent group derived from a benzene ring, a naphthalene ring, an anthracene ring or a biphenyl group, which are each independently and may have a substituent, and are preferably a source. From the base of the benzene ring. Examples of the substituent include a halogen atom; a linear or branched alkyl group having 1 to 6 carbon atoms such as a methyl group or an ethyl group; an alkenyl group such as a vinyl group; and a carbon number of 2 to 7 such as a methoxycarbonyl group or an ethoxycarbonyl group; a linear or branched alkoxycarbonyl group; a linear or branched alkoxy group having 1 to 6 carbon atoms such as a methoxy group or an ethoxy group; a 6 to 12 aromaticoxy group having a carbon number of phenoxy group or a benzyloxy group; A dialkylamine group having an alkyl group having 1 to 6 carbon atoms, such as an amine group or a diisopropylamino group. Among these, an alkyl group having 1 to 3 carbon atoms is preferable, and a methyl group is particularly preferable. Among them, Ar ^{1 1} to Ar ^{1 4} are all unsubstituted aromatic ring groups.

R ^{1 1} and R ^{1 2 are} preferably phenyl, naphthyl, anthryl, pyridyl, triazolyl, pyrazolyl, quinolin which are each independently and may have a substituent. The quinoxalinyl group, the thienyl group, or the biphenyl group is preferably a phenyl group, a naphthyl group or a biphenyl group, and more preferably a phenyl group. The above substituent is an aromatic ring group which can be contained in Ar ^{1 1} to Ar ^{1 4} , and has a group as exemplified above.

A compound having a repeating unit of the structure represented by the general formula (I), for example, a method proposed by a city or the like (Polymers for Advanced Tecnologies, 7巻, 31 pages, 1996; Japanese Patent Laid-Open No. Hei 9-188756) synthesis.

Preferred examples of the configuration shown in the general formula (I) are as follows, but are not limited to these.

The hole injecting/transporting material of the polymer compound having a hole transporting portion in the molecule is preferably a homopolymer having a structure represented by the general formula (I), or a copolymer with any other monomer. . When it is a copolymer, the structural unit represented by the general formula (I) preferably contains 50 mol% or more, and more preferably 70 mol% or more.

Further, the hole injection/transport material of the polymer compound may contain a plurality of structures of the general formula (I) in a compound. Further, a plurality of compounds containing a structure represented by the general formula (I) may be used in combination.

The hole injection/transport material composed of the polymer compound is, for example, a conjugated polymer such as polyfluorene, polypyrrole, polyaniline, polythiophene or polyparaphenylene.

The aromatic amine compound of the hole injection/transport material is, for example, a compound having a triarylamine structure, and may be suitably used in a compound for forming a material for a hole injection/transport layer in an organic electric field light-emitting element. Choose to use.

The hole injection/transport material is a compound known in the art other than the compound having the structure represented by the above general formula (I). Such a known compound is, for example, an aromatic diamine compound in which a tertiary aromatic amine unit is bonded, such as 1,1-bis(4-di-p-tolylamidophenyl)cyclohexane (Japanese Patent Application) Kaizhao 59-194393); a condensed aromatic group containing two or more tertiary amines represented by 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl The ring is an aromatic amine in which a nitrogen atom is substituted (Japanese Patent Laid-Open No. Hei 5-234681); a derivative of triphenylbenzene and an aromatic triamine having a starburst structure (U.S. Patent No. 4,923,774); N,N' An aromatic diamine such as diphenyl-N,N'-bis(3-methylphenyl)biphenyl-4,4'-diamine (U.S. Patent No. 4,764,625); α,α,α', α'-Tetramethyl-α,α'-bis(4-di-p-tolylamidophenyl)-p-xylene (Japanese Patent Laid-Open No. Hei-3-269084); the monolithic molecule is a stereo asymmetric triphenylamine derivative (Japanese Patent Laid-Open No. Hei-4-129271); a compound in which a plurality of fluorenyl groups are substituted with an aromatic diamine group (Japanese Patent Laid-Open No. Hei 4-175395); a tertiary aromatic amine unit is bonded by a vinyl group; aromatic A diamine (Japanese Patent Laid-Open No. Hei-4-264189); an aromatic diamine having a styryl structure (Japanese Patent Laid-Open No. Hei-4-290851); a compound in which an aromatic tertiary amine unit is bonded by a thienyl group ( Japanese Patent Laid-Open No. Hei 4-304466); a starburst type aromatic triamine (Japanese Patent Laid-Open No. Hei-4-308688); a benzylphenyl compound (Japanese Patent Laid-Open No. Hei-4-364153); A tertiary amine linker (Japanese Patent Laid-Open No. Hei 5-25473); a triamine compound (Japanese Patent Laid-Open No. Hei 5-239455); a bipyridylamine-based biphenyl group (Japanese Patent Laid-Open No. Hei 5-320634) N,N,N-triphenylamine derivative (Japanese Patent Laid-Open No. 6-1972); with brown Aromatic diamine of the structure (Japanese Patent Laid-Open No. Hei 7-138562); diaminophenylphenanthridine derivative (Japanese Patent Laid-Open No. Hei 7-252474); bismuth compound (Japanese Patent Laid-Open No. 2-311591)公报 ) 矽 矽 矽 矽 矽 矽 矽 矽 矽 矽 矽 矽 矽 矽 矽 矽 矽 矽 矽 矽 矽 矽 矽 矽 矽 矽 矽 矽 矽 矽 ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; No.); quinacridone compounds and the like.

These compounds may be used alone or in combination of two or more kinds as needed.

In the film-forming composition of the present invention, the content of the hole injection/transport material is usually 0.05% by weight or more, preferably 1% by weight or more. However, it is usually 50% by weight or less, preferably 30% by weight or less.

[Electron acceptor compound]

The electron acceptor compound to be contained in the film-forming composition of the present embodiment may, for example, be a salt of an aromatic boron compound or a salt thereof, a metal halide, a Lewis acid, an organic acid, an aromatic amine or a metal halide. One or two or more compounds are selected from the group consisting of a salt of an aromatic amine and a Lewis acid. These electron acceptor compounds are used in combination with a hole injection/transport material, and the conductivity of the hole injection layer can be improved by oxidizing the hole injection/transport material.

Preferred examples of the aromatic boron compound or a salt thereof are shown below, but are not limited thereto.

Among these, it is preferable to be the above (D-30).

Further, the electron accepting compound is one or more compounds selected from the group consisting of a metal halide, a Lewis acid, an organic acid, a salt of an aromatic amine and a metal halide, and a salt of an aromatic amine and a Lewis acid. Specific examples are the compounds shown below.

Further, the film-forming composition of the present invention, the weight ratio of the compound containing an electron acceptor ratio W _e and the hole injection / transport material comprising by weight of the above ratio W _p W _e / W _p based 0.001, preferably 0.01 the above. However, it is usually 1 or less, preferably 0.4 or less.

[water content]

In the film-forming composition of the present invention, as described above, in order to achieve uniformity of the film formed by the inkjet film formation method and to prevent deterioration of the organic electroluminescent device, it is preferable that the amount of water is small, specifically, The content of water contained in the film composition is preferably 1% by weight or less, particularly preferably 0.1% by weight or less, more preferably 0.05% by weight or less.

Therefore, it is preferable to use a solvent or a hole injection/transport material and/or an electron acceptor used for preparing a film-forming composition in accordance with the amount of water in the film-forming composition being equal to or less than the above upper limit. The compound is subjected to purification or drying treatment for removing moisture as needed, and then used.

[Other ingredients]

In addition to the solvent, the hole injection/transport material, and/or the electron acceptor compound, the film-forming composition of the present invention may contain various additives such as a leveling agent and an antifoaming agent, as needed. Further, a binder resin to be described later may be contained.

[Configuration of Organic Electric Field Light-Emitting Element]

Next, an organic electroluminescent device produced by using the film-forming composition of the present invention will be described.

1a to 1c are cross-sectional explanatory views showing an example of an organic electroluminescence device having a thin layer formed using the film-forming composition of the present invention.

The organic electroluminescent device 100a shown in FIG. 1a includes a substrate 101 and an anode 102, a hole injection layer 103, a light-emitting layer 105, and a cathode 107 which are sequentially laminated on the substrate 101.

The substrate 101 is a support of the organic electric field light-emitting element 100a. The material for forming the substrate 101 is, for example, a quartz plate, a glass plate, a metal plate, a metal foil, a plastic film, a plastic sheet, or the like. Among these, transparent plastic sheets such as glass sheets, polyester, polymethacrylate, polycarbonate, and polyfluorene are preferable. Further, when the substrate 101 is made of plastic, it is preferable to provide a dense yttrium oxide film or the like on one or both sides of the substrate 101 to improve gas barrier properties.

The anode 102 is provided on the substrate 101 and has a function of injecting a hole into the hole injection layer 103. The material of the anode 102 is a metal such as aluminum, gold, silver, nickel, palladium or platinum; a conductive metal oxide such as an oxide of indium and/or tin; a halogenated metal such as copper iodide; carbon black; Conductive polymers such as thiophene), polypyrrole, and polyaniline, and the like.

The method for forming the anode 102 is generally performed by sputtering, vacuum deposition, or the like on the substrate 101; fine particles such as silver or fine particles such as copper iodide, carbon black, conductive metal oxide fine particles, or conductive polymer fine powder. And a method of dispersing in a suitable binder resin solution and then applying it on the substrate 101; a method of directly forming a conductive polymer film on the substrate 101 by electrolytic polymerization; and a method of applying a conductive polymer solution on the substrate 101 Wait. Further, it is preferable that the anode 102 generally has a visible light transmittance of 60% or more, particularly preferably 80% or more. The thickness of the anode 102 is usually 1000 nm or less, preferably 500 nm or less, and usually 5 nm or more, preferably 10 nm or more.

The hole injection layer 103 provided on the anode 102 is preferably formed using the film-forming composition of the present invention, and is preferably formed by a wet film formation method. Since the organic electroluminescent element is formed by laminating a plurality of layers composed of organic compounds, uniformity of the film quality is a very important factor. When the layer formation is carried out by the wet film formation method, depending on the material and the underlying properties, a coating method such as a spin coating method or a spray method, or a printing method such as an inkjet method or a screen printing method may be employed. Knowing the film formation method. From the standpoint of using high-definition patterning to form a uniform film in a desired region, an ink jet method is preferred. In particular, when a patterned electrode or a pixel is formed with irregularities by a partition wall, and a layer composed of an organic compound is provided on a specific region of the remaining substrate surface, an ink jet method is preferably employed.

The hole injection layer 103 is preferably formed using a hole injection/transport material and an electron accepting compound capable of oxidizing the hole injection/transport material. The film thickness of the hole injection layer 103 thus formed is usually 5 nm or more, preferably 10 nm or more. However, it is usually 1,000 nm or less, preferably 500 nm or less.

The light-emitting layer 105 is provided on the hole injection layer 103, and the electrons injected from the cathode 107 and the holes transported from the hole injection layer 103 are efficiently combined between the electrodes to which the electric field is applied. And formed by re-bonding and efficient light-emitting materials. The material forming the light-emitting layer 105 may, for example, be a metal complex such as an aluminum complex of 8-hydroxyquinoline; a metal complex of 10-hydroxybenzo[h]quinoline; a bisstyrylbenzene derivative. a bisstyryl aryl derivative; a metal complex of (2-hydroxyphenyl)benzothiazole, a low molecular luminescent material such as a silole derivative; in poly(p-phenylene), poly a polymer compound such as [2-methoxy-5-(2-ethylhexyloxy)-1,4-benzene-extended ethylene], poly(3-alkylthiophene) or polyvinylcarbazole mixed with luminescence Materials and materials for electronically moving materials, etc.

Further, for example, a metal complex such as an aluminum complex of 8-hydroxyquinoline is used as a main material, and a condensed polycyclic aromatic compound such as a thick tetraphenyl derivative such as rubrene, a quinacridone derivative or hydrazine is used. Rings, etc., doping 0.1 to 10% by weight of the main material, can greatly improve the light-emitting characteristics of the component, especially the drive stability. These materials are formed on the hole injection layer 103 by a wet film formation method such as a vacuum deposition method or an inkjet film formation method. The film thickness of the light-emitting layer 105 thus formed is usually 10 nm or more, preferably 30 nm or more. However, it is usually 200 nm or less, preferably 100 nm or less.

The cathode 107 has an effect of performing electron injection on the light-emitting layer 105. The material used for the cathode 107 is preferably a metal having a lower work function, for example, an appropriate metal such as tin, magnesium, indium, calcium, aluminum, silver, or the like. Specific examples are low-work function alloy electrodes such as magnesium-silver alloys, magnesium-indium alloys, and aluminum-lithium alloys. The film thickness of the cathode 107 is generally the same as that of the anode 102.

For the purpose of protecting the cathode 107 composed of a low work function metal, a metal layer having a high work function and a stable atmosphere can be further laminated thereon, whereby the stability of the element can be effectively improved. In order to achieve this purpose, metals such as aluminum, silver, copper, nickel, chromium, gold, and platinum are used. Further, by inserting an extremely thin insulating film (having a film thickness of 0.1 to 5 nm) such as LiF, MgF ₂ or Li ₂ O between the interface between the cathode 107 and the light-emitting layer 105, the element efficiency can be improved.

Fig. 1b is an explanatory view showing a function-separating type light-emitting element. The organic electroluminescent element 100b shown in Fig. 1b is provided with a hole transport layer 104 between the hole injection layer 103 and the light-emitting layer 105 before being lifted to enhance the light-emitting characteristics of the element. The other layers have an organic structure as shown in Fig. 1a. The same configuration of the electric field light-emitting element 100a.

The material of the hole transport layer 104 must belong to a material which is highly efficient in injection of holes generated from the hole injection layer 103 and which can efficiently transport the injected holes. Therefore, it is required that the free potential is small, the hole mobility is large, the stability is excellent, and it is less likely to be trapped impurities during manufacture or use. Further, in order to form a layer directly adjacent to the light-emitting layer 105, it is preferable not to contain a substance which will illuminate the light.

The hole injecting/transporting material forming the hole transporting layer 104 is the same compound as exemplified as the hole injecting/transporting material in the film forming composition of the present invention. Further, there are polymer materials such as polyvinyl carbazole, polyethylene triphenylamine, and polyphenylene ether oxime containing tetraphenylbenzidine. The hole transport layer 104 is formed by laminating the hole injection/transport material by a wet film formation method such as an inkjet film formation method or a vacuum deposition method on the hole injection layer 103. The thickness of the hole transport layer 104 thus formed is usually 10 nm or more, preferably 30 nm. However, it is usually 300 nm or less, preferably 100 nm or less.

Fig. 1c is a view showing another embodiment of the functionally separated light-emitting device. The organic electroluminescent element 100c shown in Fig. 1c is provided with an electron transport layer 106 between the light-emitting layer 105 and the cathode 107, and the other layers have the same structure as the organic electric field light-emitting element 100b shown in Fig. 1b.

For the compound used in the electron transport layer 106, it is required to easily perform electron injection from the cathode 107, and the electron transporting ability is larger. Such an electron transporting material may, for example, be an aluminum complex of 8-hydroxyquinoline, An oxadiazole derivative, or a compound dispersed in a resin such as polymethyl methacrylate (PMMA), a phenanthroline derivative, 2-tert-butyl-9,10-N,N'-dicyano group Diimine, n-type hydrogenated amorphous tantalum carbide, n-type zinc sulfide, n-type zinc selenide, and the like. The electron transport layer 106 is formed by using a wet film formation method such as an inkjet film formation method or a vacuum deposition method, and is deposited on the light-emitting layer 105. The film thickness of the electron transport layer 106 thus formed is usually 5 nm or more, preferably 10 nm or more. However, it is usually 200 nm or less, preferably 100 nm or less.

Further, the organic electroluminescent device of the present invention is not limited to the drawings. For example, a structure opposite to that shown in FIGS. 1a to 1c can be formed in which a cathode 107, a light-emitting layer 105, a hole injection layer 103, and an anode 102 are sequentially laminated on a substrate 101. Further, at least one of them may have high transparency and an organic electric field light-emitting element may be provided between the two substrates. Further, the layer containing the hole injecting/transporting material and the electron accepting compound is not necessarily not the hole injecting layer 103 adjacent to the anode 102, and may be provided between the anode 102 and the light emitting layer 105, particularly It is preferable to inject the layer 103 into the hole. Further, any layer may be provided between the layers shown in FIGS. 1a to 1c. Further, although not shown, a wall-like structure (so-called "bank") surrounded by a pixel and made of an insulating material, a partition wall dividing the cathode, a nonlinear element for driving the pixel, or the like may be provided.

[Method of Manufacturing Organic Electric Field Light-Emitting Element]

A method for producing an organic electroluminescence device having a thin layer formed by an inkjet film formation method using the film formation composition of the present invention will be described.

When the organic electroluminescent elements 100a to 100c shown in FIGS. 1a to 1c are produced, the anode 102 is formed on the substrate 101 by sputtering, vacuum deposition, or the like. On the anode 102, at least one of the hole injection layer 103 and the hole transport layer 104 is formed by an inkjet film formation method using the composition of the present invention. The light-emitting layer 105 is formed on the hole injection layer 103 and/or the hole transport layer 104 by a vacuum deposition method or an inkjet film formation method. The electron transport layer 106 is formed on the light-emitting layer 105 by a vacuum deposition method or an inkjet film formation method as needed. A cathode 107 is formed on the light emitting layer 105 or the electron transport layer 106.

When at least one of the hole injection layer 103 and the hole transport layer 104 is formed by an inkjet film formation method, usually, in the amount of the hole injection/transport material and/or the electron acceptor compound, An additive such as a binder resin or a coating improver which does not become a hole trap is added as needed, and is dissolved to prepare a coating liquid (that is, a film forming composition). This composition is applied onto the anode 102 by an inkjet film formation method, and at least one of the hole injection layer 103 and the hole transport layer 104 is formed by drying.

Further, the content of the binder resin is preferably from 50% by weight or less, particularly preferably 30% by weight or less, based on the degree of hole mobility, and is preferably substantially not contained. The case of bonding resin is preferred.

Further, when a layer containing a hole injecting/transporting material and/or an electron transporting compound is formed, after the ink jet film forming and drying step, if the heating step is further passed, the obtained film is reduced. The residual solvent, the amount of water mixed in the ink jet film forming step, and the like can improve the device characteristics. Specifically, after forming a layer containing a hole injection/transport material and/or an electron acceptor compound by an inkjet film formation method, it is convenient to heat the substrate by means of a hot plate, an oven, or the like. In order to sufficiently obtain the effect by the heat treatment, it is preferable to carry out the treatment at 100 ° C or higher. The heating time is usually set to about 1 minute to 8 hours. According to this, the layer containing the hole injection/transporting material and/or the electron accepting compound formed by the inkjet film formation method is roughened by the surface, so that the surface of the anode 102 such as ITO can be removed. Degree, causing a problem of short circuit when the component is fabricated.

[Examples]

Hereinafter, the present embodiment will be more specifically described based on examples, comparative examples, and reference examples. Further, the present embodiment is not limited to the description of the following embodiments.

In addition, the solvent property values used in the following examples and comparative examples are shown in Table 1 below.

Further, the hole injection/transport material is the compound (I-3) exemplified above, and the electron acceptor compound is the compound (D-30) exemplified above.

[Examples 1 to 23, Comparative Examples 1 to 4 (inkjet coating)] [Modulation of film-forming composition]

According to the formulation shown in Table 2, each component compound was mixed with a solvent to prepare a film-forming composition. Hereinafter, the composition for film formation prepared by the above is simply referred to as "ink".

[Evaluation of injection status]

Using the ink to be produced and using an inkjet coating device equipped with a piezoelectric driving type ejection head, the appearance of the ink when it was ejected from the nozzle of the ejection head was observed as follows.

The ink was continuously ejected from the nozzle for 5 minutes, and the emission state after 5 minutes was observed, and the number of defective nozzles in which the nozzle was clogged and the ink could not be ejected or the ink was ejected obliquely and could not be normally ejected was counted, and evaluation was performed as follows.

VG (Very Good): The ratio of the number of defective nozzles to the total number of nozzles is less than 10% G (Good): The ratio of the number of defective nozzles to the total number of nozzles is 10% or more, and less than 50% NG (Not Good): defective The number of nozzles / the total number of nozzles is more than 50%

[Evaluation of coating status]

A plurality of inks were selected from the above-mentioned prepared inks, and a coating test was performed in the following order: 1) As shown in FIG. 2a, ITO having a film thickness of 150 nm was formed on a glass substrate by sputtering, and then photolithography was performed. The anode 202 is formed by patterning of a predetermined shape, and then the bank 203 is formed on the substrate 201 by patterning of polyimine. The size of the pixel portion 204 surrounded by the bank 203 is 135 μm × 85 μm, and the arrangement of the pixel regions is 54 rows × 32 columns.

2) As shown in Fig. 2b, using the same ink-jet coating apparatus as used in the evaluation of the emission state, the portion of the pixel 204 separated by the bank 203 is ejected from the nozzle 206 of the ejection head 207. The ink 205 is applied and coated.

3) The substrate of 2) was heated at 200 ° C, and the ink was dried to obtain a film having a film thickness of about 20 nm.

4) For the substrate of 3), the state of the thin film formed in the pixel was observed with an optical microscope, and evaluation was performed according to the following criteria.

VG: Forms a substantially uniform film.

G: Although a number of spots appear, a film which spreads over the entire area of the pixel is formed.

NG: The liquid is aggregated into a dot shape, and the film cannot be sufficiently formed.

[Evaluation of the bleed width]

In Examples 21 to 23, the evaluation of the bleed width was performed for the film formed as described above.

The "bleeding width" is as shown in Fig. 3. The thickness of the ink 205 at the edge portion of the bank 203 forms the width of the uneven region.

The bleed width was determined by observation using an optical microscope.

[evaluation result]

The above evaluation results are shown in Table 2.

Further, Fig. 4 shows the relationship between the solvent composition ratio and the bleed width.

[investigation]

According to the above evaluation results, the following items are known:

[shot state]

In Examples 1 to 23, it was found that the number of defective nozzles of all the inks was small, and good ejection was possible. This phenomenon is because the boiling point of ethyl benzoate and 2-phenoxyethyl acetate is as high as 200 ° C or higher, and the vapor pressure in the normal temperature region is less than 1 torr, so that the coating liquid is not easily dried, and the nozzle is not easily blocked. Caused.

In particular, a relatively large ink is prepared by mixing a relatively high boiling point and a low vapor pressure of 2-phenoxyethyl acetate, and a good injection state can be obtained.

On the other hand, the solvent is anisole or cyclohexanone, and the nozzles of Comparative Examples 1 to 4 having a boiling point of less than 200 ° C or a solvent having a vapor pressure of more than 1 torr at 25 ° C are likely to cause nozzle failure.

[Coating state]

The inks of ethyl benzoate of Examples 5 and 14 alone, and the mixed solvents of ethyl benzoate and 2-phenoxyethyl acetate of Examples 6-8, 14-18, and 20-23 can be obtained well. Membrane. This phenomenon is considered to be because the boiling point of ethyl benzoate and 2-phenoxyethyl acetate is as high as 200 ° C or higher, and the vapor pressure in the normal temperature region is less than 1 torr, and the coating liquid is less likely to dry, so that the coating liquid is easy. It expands within the pixel, so better uniform coating properties will be obtained.

In particular, a mixed solvent coating solution of ethyl benzoate and 2-phenoxyethyl acetate can obtain a uniform film having less spots. This phenomenon is considered to be because the boiling point of 2-phenoxyethyl acetate is very high, so that the ink is not easily dried and the leveling property is very good.

[exudation width]

In Examples 21 to 23, the bleed width was 20 μm or less, and all of the inks were able to obtain a good coating state. In particular, the solvent weight ratio is lower than that of the ethyl benzoate/2-phenoxyethyl acetate=3/1, and the other examples are mixed with 2-phenoxyethyl acetate. In Example 22 and Example 23, the bleed width is particularly small. , showing a very good coating state. The reason is considered to be because the boiling point of 2-phenoxyethyl acetate is very high, so that the ink is not easily dried, and a very good leveling property can be obtained. As a result, it was found that a film having superior flatness can be obtained in a region in which more ethyl benzoate/2-phenoxyethyl acetate = 3/1 is blended with more 2-phenoxyethyl acetate.

[Examples 24 to 28 (spray coating)] [Modulation of film-forming composition]

In the same manner as in the examples 1 to 23, the components of the respective components and the solvent were mixed according to the formulation shown in Table 4 to prepare a film-forming composition (ink).

[Evaluation of spray status]

For the ink to be produced, a spray device NVD200 manufactured by Fujimori Technology Research Co., Ltd. was used, and the state in which the ink was sprayed from the nozzle was observed as follows.

After the ink spray was applied from the nozzle for 1 minute, the nozzle was left in a state of stopping spraying for 30 minutes. After being placed, the ink spray was again applied, and the spray state immediately after the spray was observed, and evaluation was performed as follows. In addition, the "normal spray" state means that the spray shape ejected from the nozzle has a substantially conical shape. If the nozzle is blocked by the hole, the spray shape of the blocked portion of the hole will be messy, and usually the spray shape will not form a conical shape.

G: Normal spray can be started from the start of re-spraying.

NG: Hole blocking phenomenon occurs.

[Evaluation of coating status]

Using the spray device NVD200 manufactured by Fujimori Technology Research Co., Ltd., as in Examples 1 to 23, the entire surface of the substrate 201 on which the anode 202 and the bank 203 have been formed is ejected from the nozzle 206 of the spray device as shown in Fig. 5 The ink is prepared and applied. The spray device supplies ink and high pressure nitrogen to the nozzle 206, and ejects ink atomized with nitrogen from the nozzle. The substrate coated with the ink was heated at 200 ° C to dry the ink, and a film having a film thickness of about 130 nm was obtained.

According to the substrate on which the thin film was formed, the coating state evaluation was performed as in Examples 1 to 23.

[Evaluation of the bleed width]

With respect to the film formed as described above, the evaluation of the bleeding width was carried out as in Examples 21 to 23.

[evaluation result]

The above evaluation results are shown in Table 3.

Further, Fig. 6 shows the relationship between the solvent composition ratio and the bleed width.

[investigation]

From the above evaluation results, the following items were known.

[spray status]

In Examples 24 to 28, it was found that no nozzle clogging occurred in all of the inks, and a good spray was applied. This phenomenon is because the boiling point of ethyl benzoate and 2-phenoxyethyl acetate is as high as 200 ° C or more, and the vapor pressure in the normal temperature range is less than 1 torr, so that the coating liquid is not easily dried, and the nozzle is not easily blocked. Caused. In particular, 2-phenoxyethyl acetate having a relatively high boiling point and a low vapor pressure is blended in a relatively large amount, and thus exhibits a good spray state.

[Coating state]

A good film was obtained for all of the inks of Examples 24 to 28. This phenomenon is considered to be because the boiling point of ethyl benzoate and 2-phenoxyethyl acetate is as high as 200 ° C or higher, and the vapor pressure in the normal temperature region is less than 1 torr, and the coating liquid is less likely to dry, so the coating liquid is easy to be It is expanded in the pixel to obtain better uniform coating properties.

[exudation width]

In Examples 24 to 28, the bleed width was 20 μm or less, and all of the inks were able to obtain a good coating state. In particular, the solvent weight ratio is more than the ethyl benzoate / 2-phenoxyethyl acetate = 3 / 1, the formulation of more than 2-phenoxyethyl acetate, examples 25 ~ 28, the bleed width will be particularly small, It exhibits a very good coating state. The reason is considered to be because the boiling point of 2-phenoxyethyl acetate is very high, so that the ink is not easily dried, and a very good leveling property can be obtained. As a result, it was found that a film having superior flatness can be obtained in a region in which more ethyl benzoate/2-phenoxyethyl acetate = 3/1 is blended with more 2-phenoxyethyl acetate.

From these results, it is understood that the ink of the present invention is suitable not only for the ink jet method but also for spray coating.

From the above examples, it was confirmed that the ink of the present invention has superior characteristics such as "not easy to dry" and "smooth coating is good", and is suitable for an ink jet method or a spray method. Further, it was confirmed that a film having superior flatness can be obtained particularly in a region in which benzoic acid ethyl ester/2-phenoxyethyl acetate = 3/1 is blended with a large amount of 2-phenoxyethyl acetate.

The ink of the present invention has superior characteristics such as "not easy to dry" and "highly uniform coating property", and various coating methods such as a rubber plate rotary printing method, such as a rubber plate rotary printing method, and the like. The same method is also applied to a coating method for supplying ink from a slit nozzle or a spin coating method.

While the invention has been described with respect to the specific embodiments of the present invention, various modifications can be made without departing from the spirit and scope of the invention.

In addition, the present application is based on the Japanese Patent Application (Japanese Patent Application No. 2005-037902) filed on Feb. 15, 2005.

100a, 100b, 100c. . . Organic electric field light-emitting element

101, 201. . . Substrate

102, 202. . . anode

103. . . Hole injection layer

104. . . Hole transport layer

105. . . Luminous layer

106. . . Electron transport layer

107. . . cathode

203. . . embankment

204. . . Pixel section

205. . . Ink

206. . . nozzle

207. . . Nozzle

1a, 1b, and 1c are cross-sectional views showing an example of a structure of an organic electroluminescence device having a thin layer formed using a film-forming composition in the embodiment.

2a and 2b are schematic views for explaining the coating test method for evaluating the coating state in Examples 1 to 23.

Figure 3 is a schematic illustration of the bleed width as assessed in the examples.

Fig. 4 is a graph showing the relationship between the solvent composition ratio and the bleeding width in Examples 21 to 23.

Fig. 5 is a schematic view showing the coating test method for evaluating the coating state in Examples 24 to 28.

Fig. 6 is a graph showing the relationship between the solvent composition ratio and the bleeding width in Examples 24 to 28.

201. . . Substrate

202. . . anode

203. . . embankment

204. . . Pixel section

205. . . Ink

206. . . nozzle

207. . . Nozzle

Claims (24)

A film-forming composition which is a composition used for film formation of a hole injection/transport layer of an organic electroluminescence device, and which contains a hole injection/transport material and/or an electron acceptor compound, and dissolves the material. And/or a liquid of the compound, characterized in that the liquid contains a solvent having an aromatic ring and/or an alicyclic ring and an oxygen atom in the molecule and having a boiling point of 200 ° C or higher or 25 ° C and a vapor pressure of 1 torr or less ( Hereinafter, the "first solvent" is used; the liquid system contains a plurality of first solvents; and the first solvent content in the composition is 3% by weight or more. The film-forming composition of claim 1, wherein the liquid system consists essentially of only the first solvent. The film-forming composition according to the first aspect of the invention, wherein the liquid system contains the first solvent and a solvent having an aromatic ring and/or an alicyclic ring and an oxygen atom in the molecule and not belonging to the first solvent (hereinafter referred to as "second solvent"), and the weight ratio of the second solvent containing the first solvent with the W ₂ comprising a weight ratio of W W _{1 2} / W ₁ lines 1 to 20. The film-forming composition of claim 3, wherein the ratio W ₂ /W ₁ is 1 to 2.5. The film-forming composition according to the first aspect of the invention, wherein the first solvent-based aromatic ester. The film-forming composition of claim 5, wherein the aromatic ester is a benzoate. For example, the film-forming composition of claim 6 of the patent scope, wherein The acid ester is ethyl benzoate. The film-forming composition according to the first aspect of the invention, wherein the first solvent is a first solvent having a higher evaporability, and the other solvent has a higher boiling point or a lower vapor pressure at 25 ° C. The low-evaporability first solvent; the ratio of the weight content W _a of the first solvent having a higher evaporability to the weight content W _b of the first solvent having a lower evaporability W _a /W _b is 1 to 20. The film-forming composition of claim 8, wherein the ratio W _a /W _b is 1 to 2.5. The film-forming composition according to the eighth aspect of the invention, wherein the first solvent having a higher evaporability is a benzoate, and the first solvent having a low evaporability is an acetate of an aromatic ring. The film-forming composition of claim 10, wherein the benzoate is ethyl benzoate and the aromatic ring is acetate 2-phenoxyethyl acetate. The film-forming composition according to the first aspect of the invention, wherein the hole injection/transport material is an aromatic amine compound, and the electron acceptor compound is an aromatic boron compound and/or a salt thereof. The film-forming composition according to the first aspect of the invention, wherein the component contains a water content of 1% by weight or less. The film-forming composition according to the first aspect of the invention, wherein the hole injection/transport material is a polymer compound having a hole transporting portion in a molecule. The film-forming composition of claim 14, wherein the polymer compound contains an aromatic tertiary amino group in the main skeleton. A polymer aromatic amine compound constituting a unit. The film-forming composition according to claim 15, wherein the polymer compound has a structure represented by the general formula (I) as a repeating unit. In the formula (I), Ar ¹¹ to Ar ¹⁴ are each independently a divalent aromatic ring group which may have a substituent; and R ¹¹ to R ¹² are each a monovalent aromatic ring group which may have a substituent; Direct bonding, or selected from the following linkages; Further, the "aromatic ring group" includes both "a group derived from an aromatic hydrocarbon ring" and "a group derived from an aromatic heterocyclic ring". The film-forming composition of claim 16, wherein the structure represented by the general formula (I) is the following formulas (I-1), (I-2), (I-3), and (I-4). Either: The film-forming composition of claim 17, wherein the structure (I-3) represented by the general formula (I) is used. The film-forming composition of the first aspect of the invention, wherein the film-forming composition has a hole injection/transport material content of 0.05 to 50% by weight. The film-forming composition of claim 12, wherein the aromatic boron compound and/or its salt is the following formula (D-30), The scope of the patent application, Paragraph 1 forming a composition, wherein the weight ratio of the electron acceptor compound content of the composition W _e and the hole injection / transporting material by weight of the content of W _p ratio W _e / W _p is 0.001~1. The film-forming composition according to the third aspect of the invention, wherein the second solvent is at least one of the following: an aromatic ester having a boiling point of less than 200 ° C and a vapor pressure at 25 ° C of more than 1 torr; ; alicyclic ketone; and alicyclic alcohol. The film-forming composition of claim 3, wherein the second solvent is anisole and/or cyclohexanone. An organic electric field light-emitting element having a hole injection/transport layer is characterized in that the hole injection/transport material is formed by the film-forming composition of the first application of the patent application.